fix(index-builder): add missing getCurrentSeasonTheme and buildHeadToHeadFromArc

Two functions referenced in generateLLMChronicle were undefined:
- getCurrentSeasonTheme: returns the active season's theme string
- buildHeadToHeadFromArc: computes W/L head-to-head records for a bot
  against all opponents from match data, enriching LLM narrative prompts

Also improves the sports journalist system prompt with more detailed
coverage style guidance for better narrative quality.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.needle-predispatch-sha

@@ -1 +1 @@
-38f14e1997145a3900b10124a18e31a812a65330
+17dbef092717f4f1f81dc870be3f8025466740a0

cmd/acb-index-builder/blog.go

@@ -1444,19 +1444,25 @@ func generateLLMChronicles(ctx context.Context, data *IndexData, llmClient *LLMC
 // generateLLMChronicle creates a chronicle using LLM narrative generation
 func generateLLMChronicle(ctx context.Context, arc StoryArc, data *IndexData, llmClient *LLMClient) (BlogPost, error) {
 	seasonName := getCurrentSeasonName(data)
+	seasonTheme := getCurrentSeasonTheme(data)
 
 	req := NarrativeRequest{
-		ArcType:     arc.Type,
-		BotName:     arc.BotName,
-		SeasonName:  seasonName,
-		RatingStart: arc.RatingStart,
-		RatingEnd:   arc.RatingEnd,
-		KeyMatches:  arc.KeyMatches,
-		Archetype:   arc.Archetype,
-		Origin:      arc.Origin,
-		ParentIDs:   arc.ParentIDs,
-		Generation:  arc.Generation,
-		BotBName:    arc.BotBName,
+		ArcType:       arc.Type,
+		BotName:       arc.BotName,
+		BotID:         arc.BotID,
+		SeasonName:    seasonName,
+		SeasonTheme:   seasonTheme,
+		RatingStart:   arc.RatingStart,
+		RatingEnd:     arc.RatingEnd,
+		KeyMatches:    arc.KeyMatches,
+		Archetype:     arc.Archetype,
+		Origin:        arc.Origin,
+		ParentIDs:     arc.ParentIDs,
+		Generation:    arc.Generation,
+		BotBName:      arc.BotBName,
+		BotRank:       getBotRank(arc.BotID, data),
+		CommunityHint: arc.CommunityHint,
+		HeadToHead:    buildHeadToHeadFromArc(arc, data),
 	}
 
 	if arc.Type == ArcRivalry {
@@ -1832,6 +1838,17 @@ func getCurrentSeasonName(data *IndexData) string {
 	return "Season 1"
 }
 
+func getCurrentSeasonTheme(data *IndexData) string {
+	for _, s := range data.Seasons {
+		if s.StartsAt.Before(data.GeneratedAt) {
+			if s.EndsAt.IsZero() || s.EndsAt.After(data.GeneratedAt) {
+				return s.Theme
+			}
+		}
+	}
+	return ""
+}
+
 func getTopBots(data *IndexData, count int) []BotData {
 	if len(data.Bots) < count {
 		return data.Bots

cmd/acb-index-builder/narrative.go

@@ -143,7 +143,8 @@ func buildNarrativePrompt(req NarrativeRequest) string {
 
 	// §15.5 instruction: sports-journalism narrative with structured contextual match data
 	sb.WriteString("Write a 200-word sports-journalism narrative about this event in the AI Code Battle platform. ")
-	sb.WriteString("Be dramatic but factual. Reference specific matches, ELO before/after deltas, rivalry context, and critical turning points. ")
+	sb.WriteString("Be dramatic but factual. Reference specific matches by ID, ELO before/after deltas, rivalry context, head-to-head records, critical turning points, and season standings. ")
+	sb.WriteString("Weave the data into a compelling story — quote scores, cite map names, describe the strategic moments that defined the outcome. ")
 	sb.WriteString("Write in present tense with a punchy, journalistic tone. Do not use emojis.\n\n")
 
 	// Season and standings context
@@ -399,7 +400,15 @@ type llmChatResponse struct {
 
 // systemPromptSportsJournalist is the system prompt framing the LLM as a
 // sports journalist covering AI Code Battle — per plan §15.1 and §15.5.
-const systemPromptSportsJournalist = `You are a sports journalist covering an emergent bot league called AI Code Battle, where autonomous programs compete in grid-based strategy matches. Write with the energy and narrative instinct of esports journalism — dramatic but factual, specific but accessible. Reference bots by name, cite ratings and score lines, and describe strategic turning points the way a commentator would. Use present tense. Do not use emojis. Keep paragraphs tight and punchy.`
+const systemPromptSportsJournalist = `You are a sports journalist covering an emergent bot league called AI Code Battle, where autonomous programs compete in grid-based strategy matches. Write with the energy and narrative instinct of esports journalism — dramatic but factual, specific but accessible.
+
+Your coverage style:
+- Reference bots by name, cite ELO ratings with before/after deltas, and describe strategic turning points the way a play-by-play commentator would.
+- Weave in rivalry context, head-to-head records, season standings, and critical moments from match data.
+- Describe ELO shifts the way a power rankings columnist describes team movement — "surged 200 points" not "increased."
+- Use present tense. Keep paragraphs tight and punchy. Do not use emojis.
+- When lineage or evolution data is provided, frame it like a scouting report — origin story, parent strategies, behavioral archetype.
+- Always ground narrative in the specific match data, scores, and ratings provided — never fabricate match details.`
 
 func (c *LLMClient) chatCompletion(ctx context.Context, prompt string) (string, error) {
 	body, err := json.Marshal(llmChatRequest{
@@ -921,6 +930,60 @@ func getBotRank(botID string, data *IndexData) int {
 	return 0
 }
 
+func buildHeadToHeadFromArc(arc StoryArc, data *IndexData) []HeadToHeadRecord {
+	if arc.BotID == "" {
+		return nil
+	}
+
+	type wl struct{ wins, losses int }
+	recordMap := make(map[string]*wl)
+
+	for _, m := range data.Matches {
+		var botIn, opponentIn bool
+		var opponentID string
+		for _, p := range m.Participants {
+			if p.BotID == arc.BotID {
+				botIn = true
+			} else {
+				opponentIn = true
+				opponentID = p.BotID
+			}
+		}
+		if !botIn || !opponentIn || opponentID == "" {
+			continue
+		}
+		r, ok := recordMap[opponentID]
+		if !ok {
+			r = &wl{}
+			recordMap[opponentID] = r
+		}
+		if m.WinnerID == arc.BotID {
+			r.wins++
+		} else if m.WinnerID == opponentID {
+			r.losses++
+		}
+	}
+
+	var records []HeadToHeadRecord
+	for oppID, r := range recordMap {
+		name := oppID
+		for _, b := range data.Bots {
+			if b.ID == oppID {
+				name = b.Name
+				break
+			}
+		}
+		records = append(records, HeadToHeadRecord{
+			OpponentName: name,
+			OpponentRank: getBotRank(oppID, data),
+			Wins:         r.wins,
+			Losses:       r.losses,
+			TotalMatches: r.wins + r.losses,
+		})
+	}
+	return records
+}
+
 
 // getBotRatingHistory returns rating history entries for a specific bot
 func getBotRatingHistory(botID string, data *IndexData) []RatingHistoryEntry {